open.source/magic-wormhole-transit-relay
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Merge branch 'pr13'

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This commit is contained in:
Brian Warner 2020-05-21 23:08:06 -07:00
commit ac7415a4d0
1 changed files with 41 additions and 80 deletions
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105
src/wormhole_transit_relay/transit_server.py
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@ -3,6 +3,7 @@ import re, time, json
from collections import defaultdict
from twisted.python import log
from twisted.internet import protocol
from twisted.protocols.basic import LineReceiver
from .database import get_db
SECONDS = 1.0
@ -23,11 +24,16 @@ def blur_size(size):
return round_to(size, 1e6)
return round_to(size, 100e6)
class TransitConnection(protocol.Protocol):
class TransitConnection(LineReceiver):
delimiter = b'\n'
# maximum length of a line we will accept before the handshake is complete.
# This must be >= to the longest possible handshake message.
MAX_LENGTH = 1024
def __init__(self):
self._got_token = False
self._got_side = False
self._token_buffer = b""
self._sent_ok = False
self._mood = "empty"
self._buddy = None
@ -48,14 +54,33 @@ class TransitConnection(protocol.Protocol):
self._log_requests = self.factory._log_requests
self.transport.setTcpKeepAlive(True)
def dataReceived(self, data):
if self._sent_ok:
def lineReceived(self, line):
# old: "please relay {64}\n"
old = re.search(br"^please relay (\w{64})$", line)
if old:
token = old.group(1)
return self._got_handshake(token, None)
# new: "please relay {64} for side {16}\n"
new = re.search(br"^please relay (\w{64}) for side (\w{16})$", line)
if new:
token = new.group(1)
side = new.group(2)
return self._got_handshake(token, side)
self.sendLine(b"bad handshake")
if self._log_requests:
log.msg("transit handshake failure")
return self.disconnect_error()
def rawDataReceived(self, data):
# We are an IPushProducer to our buddy's IConsumer, so they'll
# throttle us (by calling pauseProducing()) when their outbound
# buffer is full (e.g. when their downstream pipe is full). In
# practice, this buffers about 10MB per connection, after which
# point the sender will only transmit data as fast as the
# receiver can handle it.
if self._sent_ok:
if not self._buddy:
# Our buddy disconnected (we're "jilted"), so we hung up too,
# but our incoming data hasn't stopped yet (it will in a
@ -68,87 +93,23 @@ class TransitConnection(protocol.Protocol):
self._buddy.transport.write(data)
return
if self._got_token: # but not yet sent_ok
self.transport.write(b"impatient\n")
# handshake is complete but not yet sent_ok
self.sendLine(b"impatient")
if self._log_requests:
log.msg("transit impatience failure")
return self.disconnect_error() # impatience yields failure
# else this should be (part of) the token
self._token_buffer += data
buf = self._token_buffer
# old: "please relay {64}\n"
# new: "please relay {64} for side {16}\n"
(old, handshake_len, token) = self._check_old_handshake(buf)
assert old in ("yes", "waiting", "no")
if old == "yes":
# remember they aren't supposed to send anything past their
# handshake until we've said go
if len(buf) > handshake_len:
self.transport.write(b"impatient\n")
if self._log_requests:
log.msg("transit impatience failure")
return self.disconnect_error() # impatience yields failure
return self._got_handshake(token, None)
(new, handshake_len, token, side) = self._check_new_handshake(buf)
assert new in ("yes", "waiting", "no")
if new == "yes":
if len(buf) > handshake_len:
self.transport.write(b"impatient\n")
if self._log_requests:
log.msg("transit impatience failure")
return self.disconnect_error() # impatience yields failure
return self._got_handshake(token, side)
if (old == "no" and new == "no"):
self.transport.write(b"bad handshake\n")
if self._log_requests:
log.msg("transit handshake failure")
return self.disconnect_error() # incorrectness yields failure
# else we'll keep waiting
def _check_old_handshake(self, buf):
# old: "please relay {64}\n"
# return ("yes", handshake, token) if buf contains an old-style handshake
# return ("waiting", None, None) if it might eventually contain one
# return ("no", None, None) if it could never contain one
wanted = len("please relay \n")+32*2
if len(buf) < wanted-1 and b"\n" in buf:
return ("no", None, None)
if len(buf) < wanted:
return ("waiting", None, None)
mo = re.search(br"^please relay (\w{64})\n", buf, re.M)
if mo:
token = mo.group(1)
return ("yes", wanted, token)
return ("no", None, None)
def _check_new_handshake(self, buf):
# new: "please relay {64} for side {16}\n"
wanted = len("please relay for side \n")+32*2+8*2
if len(buf) < wanted-1 and b"\n" in buf:
return ("no", None, None, None)
if len(buf) < wanted:
return ("waiting", None, None, None)
mo = re.search(br"^please relay (\w{64}) for side (\w{16})\n", buf, re.M)
if mo:
token = mo.group(1)
side = mo.group(2)
return ("yes", wanted, token, side)
return ("no", None, None, None)
def _got_handshake(self, token, side):
self._got_token = token
self._got_side = side
self._mood = "lonely" # until buddy connects
self.setRawMode()
self.factory.connection_got_token(token, side, self)
def buddy_connected(self, them):
self._buddy = them
self._mood = "happy"
self.transport.write(b"ok\n")
self.sendLine(b"ok")
self._sent_ok = True
# Connect the two as a producer/consumer pair. We use streaming=True,
# so this expects the IPushProducer interface, and uses